Beijing.– A Chinese dairy that sold milk powder linked to kidney stones in infants knew it contained a banned chemical weeks before ordering a recall, the health minister said Saturday.

One child has died and an official said the number of children sickened had risen to 432. Investigators have detained 19 people and are questioning 78 to find out how melamine was added to milk supplied to Sanlu Group Co., China's biggest milk powder producer, officials said at a news conference. They said some tainted powder was exported to Taiwan but none was sent to other foreign markets.

In Taiwan, authorities seized thousands of bags of Chinese milk powder. There was no word on whether any was consumed in Taiwan.

Chinese officials defended the speed of their response to the country's latest product safety disaster. They said authorities were only told of the contamination Monday, even though Sanlu received complaints as early as March and its tests found melamine in August.